The present disclosure generally relates to electronic data storage systems. In particular, this disclosure relates to managing the performance of a multi-tiered data storage system of a computer system.
Flash memory is a type of nonvolatile electronic memory device that stores and erases data in units referred to as “blocks.” A block stored on a flash memory chip must be erased before data can be written, or programmed, to the chip. Flash memory retains data for an extended period of time whether a flash chip is powered on or off. Flash memory is widely used for storage and data transfer in consumer devices, enterprise systems and industrial applications.
A solid-state drive (SSD) is a nonvolatile storage device that stores data persistently on one or more solid-state flash memory devices. SSDs differ from hard disk drives in that there are no moving parts involved in an SSD. A traditional hard disk drive (HDD) includes a spinning magnetic disk with a read/write head mounted on a mechanical arm or “actuator.” An SSD, by contrast, includes an array of semiconductor memories organized, electrically and logically, as a disk drive, using integrated circuits (ICs) rather than magnetic or optical storage media, to store data. An SSD may also be referred to as a “solid-state disk.”